There is a book called Personal Best by Marc Woods. He is Paralympic multiple gold medal winning swimmer. He got bone cancer as teenager and had a leg amputated from the knee down. He has also done a fair bit of climbing, Himalayan trekking, competing in the South Pole anniversary race etc.
The book is an interesting account of how someone managed to keep a positive frame of mind through difficult times, and motivate himself to go on and train and compete at a high level regardless of his disability. The book isn't a hard sell either, more of a "I've done Ok despite some setbacks, it's not been that easy though, here's some things I discovered along the way if you are interested, if not no problem". It's a quick read too -which is always useful.